Assessment of the Clinical Utility of the Rim and Comet-Tail Signs in Differentiating Ureteral Stones from Phleboliths

Abstract

In many instances, observers did not agree about whether the rim and comet-tail signs were present. The rim sign was observed in the absence of any secondary signs of urinary tract obstruction in only one (1.5%) of the 65 patients in our series (95% confidence interval, 0-5.3%). The comet-tail sign, when accompanied by secondary signs of obstruction, should indicate that an ipsilateral ureteral stone is present and not the reverse.

Suspected ureteral colic: plain film and sonography vs unenhanced helical CT. A prospective study in 66 patients

“…Computed tomography may sometimes mistake a ureteral calculus for a phlebolith [5,26]. In our series two calculi were erroneously interpreted as phleboliths, even retrospectively.…”

Secondary signs during non-enhanced helical computed tomography in the diagnosis of ureteral stones

“…26,34,35 The tissue rim sign occurs as a result of inflammation and edema in the ureteral wall surrounding the stone (Fig. 1).…”

“…A soft-tissue rim sign around a calcific focus is an important indicator of a ureteric stone, whereas a comet-tail sign around a calcific focus suggests a phlebolith, a radiologic mimic of a ureteric stone. 34 Tissue rim signs are detected in 34e76% of patients with ureteral stones. 36 It is also useful for diagnosing urolithiasis in patients with renal colic.…”

MDCT technique and imaging findings of urinary stone disease: an expanded review

“…The rim sign is a circumferential halo of soft tissue attenuation around an abdominal or pelvic calcification; this sign indicates that the calcification is ureteral (42,43). This finding usually helps distinction of stone obstruction from phleboliths (Fig.…”